At gameSheep dot com you can find a lot of online games and puzzles games.

One of my favorites is Mindfields 2204. It reminds me a bit of Lemmings only in this flash puzzle game you will have navigate a tank through various fields to try and reach the flag at the end.

All you have to use to beat each level is whatever is in your toolbox on the top right. Place all the tools at the right place and start your engine and find out if you can reach the next level of Mindfields 2204. Happy Puzzling!